Molecular simulation of different structure dopamine-modified graphene oxide and its effects on thermal and mechanical properties of the epoxy resin system

Abstract

Molecular dynamics (MD) simulations were carried out to explore the ideal structure design of graphene oxide (GO) modified by poly (dopamine) (PDA) which is more conducive to performances improvement of epoxy resin composites. The epoxy resin matrix was compounded with PDA-modified GO (PDA-GO) particles with different structures including the surface modification and the interlayer inserted modification. The interaction energy (Einter), molecular mobility (MSD), packing density (RDF), thermal and mechanical properties of different structure of PDA-GO/epoxy composites were calculated. Interestingly, it was found that the increased layer number of GO weakened the interfacial binding between GO particles and the epoxy matrix, and prevented the compact stacking of epoxy molecular chains, but the PDA-GO with inserted-modification structure displayed a desirable interfacial binding with epoxy resin and dramatically improved thermal and mechanical performances of the resulting composites. In addition, the surface-modification of single layer GO using PDA had negative effects on micro and macro performances of epoxy matrix composites. This work provided special revelation for rationally designing the structure of GO nanofillers and better exerting its excellent properties in epoxy matrix composites.